The present invention generally relates to thermal transfer type printing apparatuses, and more particularly to a thermal transfer type printing apparatus which transfers white or transparent ink on a recording paper and transfers ink of a predetermined color on top of the recording made by the white or transparent ink.
Printing apparatuses may be roughly divided into impact type printing apparatuses and non-impact type printing apparatuses. An impact type printing apparatus generally comprises a head having a plurality of wire-dots, and an image is printed on a recording paper when the wire-dots strike an ink ribbon on an ink sheet placed on top of the recording paper. However, in the impact type printing apparatus, a large mechanical noise is generated during the printing operation due to the striking action of the wire-dots. Further, there is a disadvantage in that the resolution of the printed image is poor.
On the other hand, the non-impact type printing apparatuses may be roughly divided into ink-jet type printing apparatuses and thermal transfer type printing apparatuses. An ink-jet type printing apparatus generally comprises a head having a plurality of nozzles, and the image is printed on the recording paper when ink is sprayed onto the recording paper from the nozzles. Compared to the impact type printing apparatus, the ink-jet type printing apparatus is advantageous in that only a small mechanical noise is generated during the printing operation. However, there is a disadvantage in that the nozzles are easily blocked by refuse or ink or the like which adheres to the nozzles.
A thermal transfer type printing apparatus comprises a thermal printing head. The image is printed on the recording paper when the thermal printing head heats an ink ribbon or an ink film placed on top of the recording paper. Compared to the impact type printing apparatus, the thermal transfer type printing apparatus is advantageous in that only a small mechanical noise is generated during the printing operation. Moreover, the problems of the refuse of ink adhering to the nozzles and the blocking the nozzles in the case of the ink-jet type printing apparatus will not occur in the thermal transfer type printing apparatus. However, since the thermal transfer type printing apparatus prints the image by melting ink or the ink ribbon or film and transferring the melted ink on the recording paper, a problem occurs when the surface of the recording paper is not smooth. In other words, when the surface of the recording paper is rough and includes concave portions and convex portions, the melted ink is only transferred on the convex portions of the surface of the recording paper and the melted ink will not reach the concave portions of the surface of the recording paper. As a result, it is impossible to obtain a clear printed image when the surface of the recording paper is not smooth.